Water management, and particularly storm water or waste water in its nature is dirty and it does carry loads of biological waste, but also inherently carries lots of inorganic waste in the form of plastics, fibers and other foreign objects that unfortunately on occasion enter the system, by, for example, being flushed down the toilet. These objects are not bio-degradable and must at one time or another be separated from the water and/or waste stream prior to pumping and/or biological treatment. Many times these items end up in, for example, lift stations that serve a vital function in the water management collection system.
Lift stations are typically low spots in a water management or waste water collection system. These stations “lift” the water or waste water back to a higher elevation to, for example, a manhole, to continue on its journey to the point of disposition (such as a waste treatment facility) or may be piped directly to the water facility. Most have two or more pumps, some surface mounted, most submerged directly in the waste water. Very large lift stations, generally those that have flows greater than 100,000 gallons a day, have, for example, an automated mechanical, motor-driven bar screens built prior to the entry of the station designed to continuously and automatically remove debris from the waste stream without human intervention except for system repairs and/or preventative maintenance on the system. These pumps are typically very expensive and require designated and significant additional room in the lift station to allow placement of such a device usually in small compounds, e.g., a small fenced in area. They also require a power source and a great deal of maintenance and/or repair.
If there is no such screen to remove foreign objects from the water stream, then the foreign objects are often pulled into the volutes or intakes of these pumps and may be passed through, but are also just as likely to become lodged in the impeller of the pump disabling it or breaking it or the motor driving the pump. These failures and blockages may result in an overflow of the station, and worst, of raw, untreated waste water, in the case of waste water or sewer system(s). The pumps may be broken and unable to be placed back in service once the item is physically dislodged. These sudden stoppages of the pump can stress the electrical motor enough that it fails due to, for example, high amperage overload. Even if the motor has overload protection these stoppages over time may weaken the overloads until they themselves fail. Ultimately these blockages resulting from foreign objects cause the loss of the pump impellor and/or motor, and they must be completely replaced.
The cost for repair and/or replacements are far-ranging because of variation in factors such as size, capacity, availability, application, and/or accessibility. Pumps in small commercial, industrial and municipal lift stations can cost from $1,000-$10,000 each. This is why larger stations, which consequently cost more, may decide to build motor driven, automated mechanical bar screening systems prior to the station. They are there to protect the pumps.
However, there have not been any bar screen type devices designed to be relatively simple, inexpensive, lightweight, long-lasting, and retractable, moveable, or removable allowing for a cost-effective and practical method for removing solid objects such as inorganic debris in a water disposal, accumulation, or treatment system. For example, no practical bar screen device has been designed prior to the present invention to effectively protect small lift stations from pump failure. At times operators and/or maintenance personnel have attempt to kluge together or fabricate on-site some type of inorganic debris catch device, that sometimes included a handle, to stop some of this debris. However, these devices always invariably fail due to poor design and function. Often, the inorganic debris catch design tends to stop too much debris, and tend to act as a dam eventually catching everything that comes out of the pipe(s) and becoming so overwhelmed by material that they break, fail, or fall into the station due to poor fastening or structural strength, thus buckling under the weight. The operator or maintenance person abandons or disposes of these devices eventually, resigning themselves to accepting the previous status quo. As a professional in this field for over 20 years I have experienced and seen this frustration time and time again, these problems were the nexus of this invention. This invention uniquely finds the perfect solution in form and function. This uniqueness is in the light weight removable/retractable design. The bar screen is superior to any style of inorganic debris catch device design because, for example, the bars allow for water to flow free through the bars and allow small items such as paper and biological debris. Other designs previously tried tend to encumber waste or water with smaller debris, stopping it as soon as it enters the baskets. The bar screen however allow for the continual flow of water to push smaller debris through the bars or down the length of the bars to accommodate biologically debris passing through while catching debris not appropriate to pass through a pump. This invention is the first to use the design and function of a bar screen and design it for installation and purpose inside the lift station to provide outstanding safe guards for the pump station, and do in a lightweight compact efficient way directly in the station without expensive alterations, automation, or mechanical equipment.
Although pump manufacturers have designed some pumps with grinders integrated in their housing to cut and grind up the foreign material, these “grinder” pumps work only so well and eventually fall prey to the same issues that normal solid handling pumps do. Nothing as of yet has been designed to remove the debris in these small systems until the creation of the present invention.